Can 60 days of feeding lead to increased fitness for transport in cull dairy cows?

Welfare of cull cows during transport to slaughter is a current concern in the Canadian dairy industry. Cull cows sold through auction often have a high prevalence of lameness, low body condition score (BCS), hock lesions, and udder engorgement. To evaluate whether drying off and feeding cull dairy cows before transport can mitigate these challenges, 45 cows designated for culling were randomly assigned to either be fed for 60 d after being dried off (Fed; n = 24) or to serve as controls by being sent directly to slaughter (Direct; n = 21). Two Fed cows were removed for health reasons before completing the feeding period. Both Fed and Direct cows were assessed for locomotion (5-point scale), BCS (5-point scale), hock lesions (3-point scale), udder engorgement (3-point scale) and body weight at the time of enrollment. Fed cows, locomotion, BCS, hock, and udder engorgement scores were assessed weekly until slaughter. Weights of the Fed cows were measured again the day before slaughter. Mixed linear regression models were used to assess continuous outcomes BCS and weight. Mixed logistic regression models were used to assess dichotomous outcomes presence of hock lesions and lameness. Fed cows gained an average of 116.9 kg over the feeding period (SE ± 8.20). Fed cows had an average weight at slaughter of 834.2 kg, whereas Direct cows' average weight was 767.3 kg (SE ± 26.8). The Fed cows' average BCS at the start of the trial was 2.4, and at slaughter was 3.6, with an average gain of 1.2 BCS points. At slaughter, proportion of udders involuted in the Fed group was 45.1% (10 out of 22) and in the Direct cows, was 0% (0 out of 21). There were no differences found in locomotion or hock lesions between the Fed and Direct groups. It is important to weigh potential benefits for the Fed cows with the fact that Direct cows did not endure a drying off procedure, nor were they placed at risk of potential adverse health events. However, despite these potential limitations, due to the improved BCS and udder engorgement scores, cows fed for 60 d may be better prepared for transportation to slaughter, as well as sell for a higher price due to increased body weight and body condition.

Colostrum insulin supplementation to neonatal Holstein bulls affects small intestinal histomorphology, mRNA expression, and enzymatic activity with minor influences on peripheral metabolism

The objectives of this study were to evaluate how varying colostral insulin concentrations influenced small intestinal development and peripheral metabolism in neonatal Holstein bulls. Insulin was supplemented to approximately 5× (70.0 μg/L; n = 16) or 10× (149.7 μg/L; n = 16) the basal colostrum insulin (12.9 μg/L; BI, n = 16) concentration to maintain equivalent macronutrient intake (crude fat: 4.1 ± 0.06%; crude protein: 11.7 ± 0.05%; and lactose: 1.9 ± 0.01%) among treatments. Colostrum was fed at 2, 14, and 26 h postnatal and blood metabolites and insulin concentration were measured at 0, 30, 60, 90, 120, 180, 240, 360, 480, and 600 min postprandial respective to the first and second colostrum meal. At 30 h postnatal, a subset of calves (n = 8/treatment) were killed to excise the gastrointestinal and visceral tissues. Gastrointestinal and visceral gross morphology and dry matter and small intestinal histomorphology, gene expression, and carbohydrase activity were assessed. Insulin supplementation tended to linearly reduce the glucose clearance rate following the first meal, whereas after the second meal, supplementation linearly increased the rate of glucose absorption and nonesterified fatty acid clearance rate, decreased the time to maximum glucose concentrations, and decreased the time to reach minimum nonesterified fatty acid concentrations. Additionally, insulin clearance rate was linearly increased by insulin supplementation following the second colostrum feeding. However, there were no overall differences between treatments in the concentrations of glucose, nonesterified fatty acids, or insulin in plasma or serum. With respect to macroscopic intestinal development, dry rumen tissue mass linearly decreased when insulin was supplemented in colostrum, and supplementation linearly increased duodenal dry tissue density (g dry matter/cm) while tending to increase duodenal dry tissue weight. Increasing the colostrum insulin concentration improved small intestinal histomorphological development in the distal small intestine, as ileal villi height and mucosal-serosal surface area index were increased by supplementing insulin. Lactase enzymatic activity linearly increased in the proximal jejunum while ileal isomaltase activity linearly decreased with insulin supplementation. These data indicate that changes in colostrum insulin concentrations rapidly affect gastrointestinal growth prioritization and carbohydrase activity. The changes in gastrointestinal ontology result in minor changes in postprandial metabolite availability and clearance.

Effect of forage types differing in undigested neutral detergent fiber concentration and forage inclusion rate on reticulo-ruminal motility and fermentation, total tract barrier function, and blood metabolites of finishing beef heifers

This study evaluated the effects of forages (BarS vs. STR) that differ in the uNDF concentration and FI rate on ruminal fermentation, total tract barrier function, reticulo-ruminal motility, and blood metabolites of beef heifers. Six ruminally cannulated Hereford × Simmental heifers (699 ± 69.1 kg BW) were used in a 6 × 6 Latin square (26 d periods) with a 2 × 3 factorial treatment arrangement. However, 1 heifer was removed from the study after period 2 due to health problems unrelated to treatment, resulting in an incomplete 6 × 6 Latin square design. Barley grain-based diets were formulated using BarS or wheat STR to alter uNDF (7.1% vs. 8.5% DM) with FI rates of 5%, 10%, or 15% of DM. There were limited interactions between the forage type and FI. DM intake was not affected (P ≥ 0.10) by forage type or FI. Use of STR vs. BarS increased uNDF intake (P < 0.001). Increasing FI increased (P < 0.001) uNDF intake for those fed 15% forage. Ruminal pH was not affected (P ≥ 0.10) by forage type; however, cattle fed 5% FI had lesser (P = 0.017) mean ruminal pH and maximum pH (P = 0.018) than those fed 10% and 15% of forage. The total SCFA concentration was not affected by forage type (P = 0.84) but cattle fed the 5% FI rate had lesser (P < 0.001) molar proportion of acetate when compared with cattle fed 10% and 15% forage. Increasing the FI rate decreased the molar proportion of propionate (P < 0.001). Feeding STR relative to BarS decreased (P = 0.041) the reticulo-ruminal contraction duration. In contrast, cattle fed the 10% and 15% FI rates had a greater (P = 0.028) contraction frequency with lower (P = 0.048) contraction area than those fed 5% forage. Plasma glucose, serum insulin, and serum amyloid A were not affected by forage type or FI rate (P ≥ 0.10). Cattle fed 15% forage had lesser (P = 0.040) concentration of serum haptoglobin when compared with cattle fed 5% or 10% forage. In conclusion, forage type used to affect the dietary uNDF concentration, and FI rate act independently suggesting that the provision of STR to increase uNDF reduces reticulo-ruminal contraction duration and total tract permeability but may not affect ruminal pH. Increasing the FI increased dietary uNDF, stabilized ruminal pH, stimulated more frequent reticulo-ruminal contractions, and may decrease the permeability of the gastrointestinal tract and systemic inflammation.

Effect of physically effective neutral detergent fiber and undigested neutral detergent fiber on eating behavior, ruminal fermentation and motility, barrier function, blood metabolites, and total tract digestibility in finishing cattle

This study evaluated the effects of physically effective neutral detergent fiber (peNDF) and undigested neutral detergent fiber (uNDF) on eating behavior, ruminal fermentation and motility, barrier function, blood metabolites, and total tract nutrient digestibility for finishing cattle. Six Simmental heifers (668 ± 28.4 kg BW) were used in a replicated 3 × 3 Latin square (21 d periods) balanced for carry-over effects. Treatments included a control (CON; Table 1) with no forage peNDF and minimal uNDF (peNDF: 0.0%, and uNDF: 4.88 ± 0.01; 95.15% barley grain, 4.51% vitamin and mineral supplement, and 0.34% urea on a DM basis). Pelleted wheat straw (PELL) was included at 10% of dietary DM by replacing barley grain to provide added uNDF but no forage peNDF (peNDF: 0.00%, and uNDF: 6.78 ± 0.02%). Finally, chopped wheat straw (STR) was included as a replacement for pelleted wheat straw to provide forage peNDF and uNDF (peNDF: 1.74 ± 0.06%, and uNDF: 6.86 ± 0.03%). Dry matter intake was not affected (P = 0.93) by treatments. Cattle fed CON spent less time ruminating (P = 0.010) and had less meals/d (P = 0.035) when compared with cattle fed STR, with those fed PELL being intermediate but not different from other treatments. Cattle fed CON had lesser ruminal pH (P = 0.020), and a greater duration that pH was < 5.5 (P = 0.020) as compared to cattle fed STR, with those fed PELL being intermediate but not different. Cattle fed CON and PELL had greater total short-chain fatty acid concentration (P = 0.003) and molar proportion of propionate (P < 0.001) when compared with cattle fed STR. Cattle fed STR had greater (P = 0.010) total ruminal pool size when compared with cattle fed CON and PELL. Cattle fed CON had greater (P = 0.043) duration between ruminal contractions when compared with cattle fed STR, with those fed PELL being intermediate. Cattle fed CON had greater serum amyloid A (P = 0.003) and haptoglobin (P < 0.001) concentration when compared with the other treatments. Cattle fed CON had greater dry matter (P < 0.001) digestibility when compared with the other treatments. In conclusion, inclusion of PELL and STR impacted eating behavior, but only STR affected ruminal fermentation, ruminal motility, systemic inflammation, and total tract nutrient digestibility in finishing cattle. These results are interpreted to suggest that the combination of peNDF and uNDF may be better than uNDF alone to adequately capture biological effects of NDF in high-concentrate diets.

The effects of feeding benzoic acid and/or active dry yeast (Saccharomyces cerevisiae) on fatty acid composition, sensory attributes, and retail shelf-life of beef longissimus thoracis

Fifty-nine Angus-cross steers (492 ± SD 36 kg) were arranged in a randomized complete block design and assigned to the following dietary treatments for the final 106 days of the finishing phase: no supplementation (CON), 0.5% benzoic acid (ACD), 3 g/steer/d active dry Saccharomyces cerevisiae (YST), or both [0.5% benzoic acid and 3 g/steer/d S. cerevisiae (AY)]. Steers were slaughtered at a commercial facility where longissimus thoracis (IMPS #107 Beef Rib) samples were retrieved and evaluated for fatty acid composition, sensory attributes, and shelf-life during a simulated retail display period. Data (N = 57) were analyzed using dietary treatment as a fixed effect, blocking weight at the beginning of the study as a random effect, and steer as the experimental unit. Muscle pH and proximate composition (moisture and intramuscular lipid) for longissimus samples were not different (P ≥ 0.39) among dietary treatments. Most fatty acid profile values and calculations were not different among dietary treatments (P ≥ 0.10); however, the n-6:n-3 ratio differed (P = 0.01), with ACD samples having lower n-6:n-3 compared with CON and YST samples while AY samples were intermediate and not different from other dietary treatments. The trained sensory panel did not detect differences among dietary treatments (P ≥ 0.23) for juiciness, beef flavor intensity, or off-flavor intensity; however, they did score AY samples as chewier than ACD samples with CON and YST samples intermediate and not different from other dietary treatments. Yet, tenderness was not different when scored by trained panelists (P = 0.10) or measured instrumentally (P = 0.21). Total color change tended to differ (P = 0.09) during the 12-d simulated retail display period with AY samples experiencing less color change compared with YST samples, while CON and ACD samples were intermediate and not different from other dietary treatments. Lipid oxidation (as measured with TBARS) tended to differ (P = 0.08) following the 12-d simulated retail display period with ACD and AY samples experiencing lower levels of oxidation compared with CON, while YST samples were intermediate and not different from other dietary treatments. Overall, these results suggest there were no negative impacts on meat quality when finishing steers were supplemented with either benzoic acid or S. cerevisiae, and there may even be advantages for fatty acid composition and oxidative stability when steers were supplemented with benzoic acid.

PSV-B-20 Effect of Physically Effective Neutral Detergent Fiber, and Undigested Neutral Detergent Fiber on Eating Behavior, Ruminal pH, Ruminal Motility, and Total Tract Permeability for Finishing Cattle

This study evaluated the effects of physically effective neutral detergent fiber (peNDF), and undigested neutral detergent fiber (uNDF) on dry matter intake (DMI), eating behavior, ruminal fermentation, and total tract permeability for finishing cattle. Simmental heifers (n=6; 667.8±28.4 kg) were used in a replicated 3×3 Latin square (21-d periods) balanced for carry-over effects. Barley grain-based diets were formulated to provide treatments with: low peNDF and low uNDF (95% barley and supplement, and 0% straw; 0FOR); low peNDF but high uNDF (85% barley and supplement, 10% pelleted straw; PEL); or high peNDF with high uNDF (85% barley and supplement, 10% chopped straw; ST). Treatment did not affect DMI (P=0.93). Heifers fed 0FOR spent less (P&lt; 0.01) time eating vs. ST, where PEL was intermediate. Time spent ruminating was greater (P=0.01) for ST than 0FOR, with PEL not differing. Heifers fed 0FOR had fewer meals/d than ST (P&lt; 0.01) and meal size was greater for 0FOR than PEL and ST (P&lt; 0.01). Feeding 0FOR reduced (P=0.02) mean ruminal pH (5.65 vs. 6.07) and increased (522 vs. 288 min/d, P=0.02) the duration that pH was &lt; 5.5 relative to ST with PEL being intermediate (5.82 and 504 min/d, respectively). Heifers fed 0FOR had greater (112.5 vs. 59.9 sec, P=0.05) time between contractions and lesser (61.45 vs. 94.58 mmHg′sec, P=0.05) contraction area compared with cattle fed ST, while PEL remained intermediate (76.73 sec and 73.29 mmHg×sec, respectively). Permeability of the gastrointestinal tract to Cr-EDTA and intestine to Co-EDTA did not differ (P≥0.11) among treatments. The data suggest that increasing uNDF improved ruminal function, but increasing uNDF with peNDF is needed to decrease the risk of ruminal acidosis in finishing cattle. The results further suggest that the use of uNDF and peNDF may provide useful information over NDF inclusion when evaluating fiber adequacy of finishing diets.

PSX-A-1 Impacts of Undigestible NDF and Grain Source in Feedlot Steers on Performance, Feeding Behavior, and Ruminal pH

Little is known about how fiber quality impacts rumen health in feedlot diets with minimal forage inclusion. The objective of the study is to investigate the interaction between undigestible NDF (uNDF) levels and grain fermentability (GF) on animal performance, feeding behavior, and ruminal pH in feedlot steers. Using a 2x2 factorial design, Angus crossbred steers (n=96, 505±54 kg) were fed an isonitrogenous and isocaloric diet containing: high uNDF (haylage; 12% uNDF) or lower uNDF (corn silage, 6% uNDF) and high (high moisture corn) or lower ruminally fermentable grain (rolled corn) yielding 4 different treatments. Following adaption, steers were fed their treatment ration for 102±14d before slaughter. Feed intake (DMI) and feeding behavior data were collected using Insentec feeders and continuous ruminal pH was measured during the last 4 weeks before slaughter using indwelling pH probes (12 steers/treatment). Liver abscesses and gut health scores were assessed at slaughter. Steers on the low uNDF diet had greater ADG (P≥0.005) and improved F:G (P≥0.005) for the first half of the finisher period. No other differences in performance traits were found for the second half or overall finisher period between uNDF and GF, or their interaction. DMI (P≥0.64) did not differ, but time spent at the feeder (min/day) was greater (P≥0.02) for low GF steers. Steers fed low uNDF had greater (P≥0.04) time per day spent with ruminal pH below pH 5.8. At slaughter, steers fed high GF treatments had greater hot carcass weights (P≥0.03). This data suggests that low uNDF can improve early gain but may result in increased SARA risk compared to high uNDF at the same forage inclusion level. However, there was limited interaction with grain processing. Further research should continue to investigate relationships between uNDF and ruminal pH, and dietary uNDF concentrations that optimize performance without compromising gut health.

PSVIII-12 Influence of Colostrum Insulin Supplementation on Brush Border Carbohydrase Activity in Neonatal Holstein Bulls

Insulin concentrations are variable in bovine colostrum (5 to 263 µg insulin/L) and its effects on gastrointestinal function in neonatal calves are unknown. The objective of this study was to determine if varying concentrations of insulin in colostrum would influence intestinal carbohydrases in neonatal Holstein bulls. Calves (n = 26; 49.11 kg, SD = 3.24) were removed from their dams after calving. They were fed 3 meals of colostrum (7% BW or 3.10 ± 0.02 L) at 2, 14 and 26 hours after birth containing one of 3 insulin concentrations: basal (16.8 µg/L; n = 8), or supplemental colostrum containing either a 5× (83.4 µg/L; n = 10) or 10× (167.5 µg/L; n = 8) increase in colostrum insulin respective to basal concentrations. At 30 hours, the animals were killed, and the gastrointestinal tract was removed for mucosal scrapings of the duodenum, proximal jejunum, and ileum. Intestinal mucosal scrapings were assayed for the following brush border carbohydrases: maltase, isomaltase, lactase and glucoamylase. Data were analyzed using the MIXED procedure of SAS with treatment and dam parity modeled as fixed effects. There was no treatment effect (P &gt; 0.05) on intestinal maltase, isomaltase and glucoamylase concentrations. However, there was a linear increase (P &lt; 0.05) in jejunal lactase activity (Unit/g of jejunum and U/g of protein) with increasing amount of insulin inclusion. These data indicate that insulin supplementation has minimal effects on activities of brush border starch degrading enzymes, but increases lactase activity in the proximal jejunum of neonatal calves.

162 Differential Late Gestation Metabolizable Energy Intake Alters Adipose-Specific Insulin Responsiveness in Antepartum Beef Cattle

We evaluated how metabolizable energy (ME) intake influences antepartum insulin sensitivity in beef cattle. Angus-Simmental cattle (primiparous: n = 17; multiparous: n = 21) were randomly assigned to treatments supplying 80 (LowME, n = 19) or 120% (HighME, n = 19) of predicted ME requirements for 53 d prepartum. At 7 d antepartum, intravenous glucose tolerance tests (IVGTT) were imposed by infusing 1.36 g glucose/kg BW0.75 and sampling from -3 to 90 min to measure plasma glucose and insulin and serum non-esterified fatty acids (NEFA) concentrations. Data were analyzed using PROC GLIMMIX with the fixed effects of treatment, parity, time (repeated), and treatment×time and considering cow(treatment) as random. Baseline glucose concentration increased (P = 0.03) and baseline insulin concentration tended to increase (P = 0.06) for HighME relative to LowME cattle irrespective (P ≥ 0.33) of parity, whereas baseline NEFA concentration was elevated (P &lt; 0.01) for LowME vs. HighME. Plasma glucose-insulin concentrations during the IVGTT did not differ (P ≥ 0.25) by treatment, treatment×time, or parity. However, serum NEFA was elevated (P &lt; 0.01) throughout the IVGTT for LowME vs. HighME cattle and tended to be affected (P = 0.09) by the treatment×time interaction as NEFA concentrations became similar at 90 min due to HighME cattle having a shallower (treatment×time: P &lt; 0.01) decremental NEFA response than LowME cattle. Low ME cattle cleared NEFA more quickly (75% increase; P &lt; 0.01) than HighME. The glucose positive incremental area-under-the-curve throughout the IVGTT tended to be lesser (P = 0.06) for heifers than cows but heifers had a blunted (P ≤ 0.05) glucose-stimulated reduction in NEFA and NEFA clearance rate compared to cows. These data demonstrate that ME provision may alter adipose insulin responsiveness in antepartum beef cattle and that heifers respond to excess glucose and NEFA differently than cows.

154 Supplementation of Late Gestation Metabolizable Energy in Beef Cows Reduces Mobilization of Body Reserves Prepartum

This study evaluated how late gestation metabolizable energy (ME) intake affects performance and metabolism in beef cattle. Primiparous (PP; n = 45) and multiparous (MP; n = 107) Angus-Simmental cows were blocked by calving date and randomly assigned to treatments providing 80 (LME; n = 52), 100 (CME; n = 51), or 120% (HME; n = 49) of ME requirements for 53 d prior to calving. Postpartum, cows were fed the same diet. Rib and rump fat depths were measured by ultrasonography on d -54, -40, -26, -13, 13, 27, and 55 relative to calving. Plasma and serum were collected on d -53, -39, -25, -10, -3, 7, 13, 27, and 55 relative to calving. Serum glucose, beta-hydroxybutyrate, non-esterified fatty acids (NEFA), and urea, and plasma insulin were measured. Data were analyzed using PROC GLIMMIX with the fixed effects of treatment, parity, and treatment×parity, and random effects of block and cow (block), accounting for repeated measures. Absolute loss of rib and rump fat prepartum was lesser (P ≤ 0.03) for HME. Primiparous heifers lost more (P &lt; 0.01) rib fat prepartum. Prepartum serum urea and NEFA were elevated (P &lt; 0.01) for LME, whereas glucose was elevated (P &lt; 0.01) for HME compared to LME. Multiparous cows had greater (P ≤ 0.02) serum NEFA and plasma insulin prepartum, whereas PP heifers had elevated (P &lt; 0.01) glucose. Treatment did not affect (P ≥ 0.56) the absolute loss of rib nor rump fat postpartum. Serum urea was greater (P &lt; 0.01) in LME than HME postpartum. Multiparous cow serum urea and beta-hydroxybutyrate postpartum was elevated (P ≤ 0.01) postpartum, whereas PP cows had elevated (P &lt; 0.01) plasma insulin. Supplementing excess ME during late gestation reduced mobilization of body reserves before calving but prepartum effects did not continue postpartum.

PSIII-A-18 The Effects of Feeding Finishing Cattle Benzoic Acid and/or Live Active Yeast (Saccharomyces Cerevisiae) on Meat Quality

In a randomized complete block design, 59 Angus-cross finishing steers were used to evaluate the effects of benzoic acid, active dry Saccharomyces cerevisiae, or a combination of both when supplemented in a high-grain finishing diet on meat quality and sensory evaluation of longissimus steaks. Steers were fed a high-moisture corn-based finishing diet for 106 d containing: no supplementation (CON), 0.5% benzoic acid (ACD), 3 g/head/d active dry S. cerevisiae (YST), or both (0.5% benzoic acid and 3 g/head/d S. cerevisiae (AY)). Cattle were humanely slaughtered at a commercial facility where 54 rib sections (CON; n=15, ACD; n=14, YST; n=15, and AY; n=11) were retrieved and used for evaluation of meat quality and trained sensory parameters. Statistical analysis was completed using PROC GLIMMIX of SAS. Longissimus pH, proximate composition, shear force, and cooking loss did not differ between treatments (P ≥ 0.10). Although no differences in lipid oxidation was detected at the beginning of the retail display (d 0), lipid oxidation levels were greater (P = 0.02) in CON vs. AY steaks following 12 days of retail display. Some colour parameters differed (P ≤ 0.04) among treatments on days 11 (L*) and 12 (a*, L*, and discolouration) of the retail display. Although dietary treatment did not impact fatty acid profiles for longissimus muscle, n-6:n-3 polyunsaturated fatty acids ratios were greater in CON and YST than in ACD longissimus (P = 0.007). Steaks from Combination (AY) supplemented steers were chewier than steaks from steers only supplemented with benzoic acid, while juiciness, tenderness, and flavour were not impacted by supplementation. These results suggest that supplementation with benzoic acid and(or) yeast does not have a substantial impact on meat quality or sensory traits.

Oversupplying metabolizable protein during late gestation to beef cattle does not influence ante- or postpartum glucose-insulin kinetics but does affect prepartum insulin resistance indices and colostrum insulin content

The objective of this study was to evaluate whether oversupplying metabolizable protein (MP) during late gestation influences glucose and insulin concentrations, and insulin resistance (IR) in late gestation and early lactation. Crossbred Hereford, first-lactation heifers were individually fed diets to supply 133% (HMP, n = 11) or 100% (CON, n = 10) of their predicted MP requirements for 55 ± 4 d (mean ± SD) prior to calving. All heifers received a common lactation ration formulated to meet postpartum requirements (103% MP and 126% ME). After feed was withheld for 12 h, cattle underwent an intravenous glucose tolerance test (IVGTT) on d -6.7 ± 0.9 and 14.3 ± 0.4 by infusing a 50% dextrose solution (1.36 g glucose/kg BW 0.75) through a jugular catheter with plasma collected at -10, 0 (immediately after infusion), 5, 10, 15, 20, 25, 30, 45, 60, 75, 90, and 120 min, respective to the infusion. Glucose and insulin concentrations were assessed. Insulin resistance indices (homeostasis model of insulin resistance [HOMA-IR], quantitative insulin sensitivity check index [QUICKI], revised quantitative insulin sensitivity check index [RQUICK], and RQUICKI incorporating serum beta-hydroxybutyrate concentrations [RQUICKIBHB]) were calculated from measurements of serum non-esterified fatty acids and beta-hydroxybutyrate and plasma glucose and insulin concentrations on d -34 ± 4, -15 ± 4, 7 ± 1, 28 ± 3, 70 ± 3, and 112 ± 3. Colostrum samples were collected within an hour of calving (prior to suckling) and analyzed for insulin concentration. Data were analyzed as a randomized block design using the PROC GLIMMIX of SAS, accounting for repeated measurements when necessary. Baseline (-10 min) plasma glucose and insulin concentrations were elevated (P ≤ 0.038) for HMP heifers during the antepartum IVGTT, but not (P ≥ 0.25) during the postpartum IVGTT. Plasma glucose and insulin concentrations throughout the antepartum or postpartum IVGTT did not differ (P ≥ 0.18) by prepartum treatment, nor did other glucose and insulin IVGTT parameters (i.e., max concentration and time to reach max concentration, nadir values, clearance rates and half-lives, area-under-the-curve, and insulin sensitivity index; P ≥ 0.20). Antepartum IVGTT IR indices indicated that HMP heifers were more (P ≤ 0.011) IR than their counterparts. Similarly, the prepartum HOMA-IR was greater (P = 0.033) for HMP heifers, suggesting increased IR. Postpartum IR indices did not (P ≥ 0.25) indicate that prepartum MP consumption impacted postpartum IR. Colostrum insulin concentration was increased (P = 0.004) by nearly 2-fold for HMP relative to CON heifers. These data demonstrate that prepartum MP overfeeding alters baseline glucose-insulin concentrations in late-pregnant beef heifers and increases colostrum insulin content without having carry-over effects on postpartum glucose-insulin concentrations and IR.

PSXIV-7 Performance and environmental benefits from biochar supplementation in beef cattle grazing systems

Reducing greenhouse gas (GHG) emissions from beef cattle production systems has continuously been recognized as an important strategy to help mitigate climate change. This experiment was conducted to determine the optimum inclusion level of biochar (Oregon Biochar Solution, White City, OR) in the diet to reduce enteric methane (CH4) emissions from beef cows. Biochar is a stable form of carbon produced through low-oxygen and high-temperature pyrolysis of organic matter (typically forestry waste). Using a 4 x 4 Latin square design, pregnant beef cows (n = 8) of similar weight and stage of pregnancy were supplemented with biochar daily at 0, 1, 2, or 3% of total dry matter intake (DMI). Biochar was added to a pellet containing 45% biochar, 42.5% wheat midds, 10% canola oil, and 2.5% dry molasses to facilitate ease of feeding and encourage biochar consumption. Each 21-day period consisted of 14 days for diet adaptation and 7 days for data collection. Enteric gas emissions were measured using C-Lock GreenFeed trailers (C-Lock Inc., Rapid City, SD, USA) and DMI was collected using Insentec feeders (Insentec, Voorsterweg, The Netherlands). Enteric CH4 emissions expressed in g CH4/day, g CH4/kg DM, and g CH4/kg BW were not affected by biochar supplementation (P ≥ 0.41), although the 3% inclusion was numerically lowest. For all parameters expressing CH4 emissions, linear and quadratic effects for inclusion rate were not significant (P ≥ 0.19). Dry matter intake and cow body weights were not affected by biochar supplementation (P ≥ 0.34). These results suggest that biochar was ineffective for reducing CH4 emissions from beef cows fed a high forage diet (50% haylage, 30% straw, 17% corn silage) with no effects on animal performance. Further research should investigate whether type of biochar or higher inclusion levels of biochar can reduce CH4 emissions from beef cattle.

PSVII-13 Performance and environmental benefits from biochar supplementation in beef cattle grazing systems

Worldwide, beef production systems represent a significant source of greenhouse gas (GHG), and enteric methane (CH4) emissions are the primary concern. The objective of this experiment was to determine whether biochar (Oregon Biochar Solution, White City, OR) supplementation can reduce CH4 emissions from grazing beef cows. Biochar is a stable form of carbon produced through the pyrolysis of organic matter (typically forestry waste). Sixty-four cows and their calves were blocked by cow body weight and calf age, and randomly allocated to 8 paddocks, each with 8 cow-calf pairs. Using a crossover design, each paddock was assigned to one of two treatments: (1) biochar supplemented at approximately 3% of estimated dry matter intake (DMI) or (2) control (no biochar). Biochar was incorporated into a pellet containing 45% biochar, 42.5% wheat midds, 10% canola oil, and 2.5% dry molasses and fed in a portable trough once daily. Each period consisted of 28 days: 21 days for biochar adaptation and 7 days for data collection. Enteric gas emissions from each paddock were measured using C-Lock GreenFeed trailers (C-Lock Inc., Rapid City, SD, USA) with pasture DMI estimated using paddock entry/exit quadrats during each sampling week. Enteric CH4 emissions expressed as g CH4/d were 249 and 260 ± 50.3 g (P ≥ 0.37) for control and biochar, respectively. Similarly, g CH4/kg DM and g CH4/kg BW were not affected (P ≥ 0.44) by biochar supplementation on pasture. Biochar supplementation did not affect estimated DMI or cow/calf body weights (P ≥ 0.15). Results suggest that biochar was ineffective for reducing methane emissions from grazing beef cows; however, measures of animal performance were not affected by biochar consumption. Further work is required to determine if type or higher inclusions of biochar can reduce CH4 emissions from beef cattle.

PSXIII-29 Late-Breaking: Relationships between feed efficiency traits, gas emissions, and calculated heat production and respiratory quotients in mature beef cows

This research evaluated relationships between feed efficiency measurements including residual feed intake (RFI), gain to feed ratio (G:F) and enteric gas production of methane (CH4), carbon dioxide (CO2), oxygen, (O2) along with calculated respiratory quotient (RQ) and heat production (HP) of mature beef cows. Sixty pregnant multiparous Angus beef cows were measured for individual intake for 10 weeks leading up to parturition. Cows were individually fed using the Insentec feeding system to measure individual feed intake. Pens of cows were rotated weekly to the C-Lock Greenfeed trailer (C-Lock Inc.) to measure gas production for a minimum 2 periods per group. Cows were weighed, body condition scored, and ultrasound performed for rib and rump fat depth every 28 days and calf birth weight was recorded. Pearson correlations were conducted to determine relationships between gas exchange measurements and feed efficiency measures. The model for RFI included ADG, pregnancy corrected BW, and ultrasound measures of rib and rump fat (R2= 0.32). Methane emissions were 263±40.3 g CH4/d in dry lot, and daily enteric CH4 emissions per kg of pregnancy corrected body weight ranging from 0.26 to 0.53 g CH4/kg pcBW. Pearson correlations found positive correlations between DMI and CH4 and CO2 (P ≤ 0.001). Pregnancy corrected BW was also positively correlated with total O2 consumption and calculated HP (P ≤ 0.001) and negatively correlated with RQ (P = 0.04). However, RFI and feed conversion ratio were not significantly correlated with gas measurements, or calculated HP or RQ (P ≥ 0.1), although DMI/kg of BW tended (P = 0.098) to be negatively correlated with O2 consumption. In conclusion, accurately identifying feed efficiency in mature beef cows continues to be a challenge. However, the inclusion of gas exchange measures and calorimetry measurements may be able to better assess metabolic efficiency in mature beef cattle.

PSX-A-21 Late-Breaking: Predicting live weight using linear body measurements in growing dairy calves

The objective of this study was to explore how linear body measurements are related to body weight and can be used to predict calf body weight using linear and machine learning models. To meet these objectives, a total of 69 Holstein calves from a commercial dairy farm were enrolled in the study from wk 2 – 8 of age. Calves were weighed and linear measurements were collected weekly. Nineteen linear measurements were obtained each week, including: poll to nose, width across the eyes, width across the right ear, neck length (NL), wither height (WH), heart girth (HG), midpiece height (MH), midpiece circumference (MC), midpiece width (MW), midpiece depth (MD), midpiece width across the 13th rib (MW13), hook height, hook width, pin height, top of pin bones width (PW), nose to tail body length, the length between the withers and pins (WPL), forearm to hoof, cannon bone to hoof. These measurements were taken using a commercial soft tape measure and calipers. Using a machine learning approach, models were generated to predict BW from calf linear measurements using Weka software 3.8.5 (University of Waikato, New Zealand) using a 10-fold cross-validation method. Both linear regression (LR) and random forest (RF) models were evaluated. Across all weeks the LR model derived 12 of the 19 traits to fit the BW model (r2 = 0.93). These included: PN, NL, WH, HG, MC, MW, MD, HW, PW, MW13, WPL. The RF model slightly reduced BW predictions (r2= 0.92). The results of this study suggest that linear models built on linear measurements can accurately estimate body weight in dairy calves. These data and models generated are important to further the development of visualized weighing systems for young dairy calves and may be used to accurately predict BW without a scale.

PSIII-5 Predicting live weight using linear body measurements in growing beef calves

The objective of this study is to investigate how linear body measurements relate to and can be used to predict calf body weight using linear and machine learning models. To meet these objectives, a total of 103 Angus cross calves were enrolled in the study from wk 2 - 8. Calves were weighed and linear measurements were collected weekly, such as: poll to nose, width across the eyes (WE), width across the right ear, neck length, wither height, heart girth (HG), midpiece height (MH), midpiece circumference, midpiece width (MW), midpiece depth (MD), hook height, hook width, pin height, top of pin bones width (PW), width across the ends of pin bones, nose to tail body length, the length between the withers and pins, forearm to hoof, cannon bone to hoof. These measurements were taken using a commercial soft tape measure and calipers. To assess relationships between traits and to fit a model to predict BW, data were analyzed using the Weka (The University of Waikato, New Zealand) software using both linear regression (LR) and random forest (RF) machine learning models. The models were trained using a 10-fold cross-validation approach. The automatically derived LR model used 11 traits to fit the data to weekly BW (r2 = 0.97), where the traits with the highest coefficients were HG, PW and WE. The RF model improved further the BW predictions (r2= 0.98). Additionally, sex differences were examined. Although the BW model continued to fit well (r2 0.97), some of the top linear traits differed. The results of this study suggest that linear models built on linear measurements can accurately estimate body weight in beef calves, and that machine learning can further improve the model fit.

PSX-B-10 Effect of undigested neutral detergent fiber concentration and forage inclusion rate on ruminal pH, reticular motility, and total tract permeability for finishing beef heifers

This study evaluated the effects of undigested neutral detergent fiber (uNDF) concentration and forage inclusion (FI) rate on dry matter (DM) intake, ruminal pH, reticular contractions, and gastrointestinal permeability for finishing beef cattle. Five ruminally cannulated Hereford′Simmental heifers (699±69.1 kg) were used in an incomplete 6×6 Latin square (26-d periods) with a 2×3 factorial treatment arrangement. Barley grain-based diets were formulated using barley silage or wheat straw to provide low or high uNDF (7.1 vs. 8.5% DM) with forage proportions of 5, 10, or 15% of dietary DM. Dry matter intake (P ≥ 0.10) and eating time (P ≥ 0.13) were not affected by uNDF, FI, or uNDF′FI. With low uNDF diets, increasing FI numerically (P = 0.02) increased rumination time (min/d); while, with high uNDF diets, rumination time increased with 5 to 10% FI, but not thereafter (P = 0.03). Mean ruminal pH was not affected by uNDF (6.17 vs. 6.19; P = 0.08), but increased with increasing FI (6.04b, 6.23a, and 6.28a; P = 0.02). Duration of ruminal pH &lt; 5.5 was not affected by uNDF but tended (P = 0.07) to be reduced with increasing FI. High uNDF diet tended to increase the frequency of reticular contractions (1.43 vs. 1.51 contractions/min; P = 0.07) but decreased the contraction duration (13.2 vs. 14.1 sec; P = 0.04). Increasing FI increased contraction frequency (1.39b, 1.50a, and 1.53a contractions/min; P = 0.03) and tended to reduce contraction duration as forage increased from 5 to 10 and 15% (14.3, 13.1, and 13.6 sec; P = 0.07). Feeding high uNDF decreased (P = 0.05) permeability of the gastrointestinal tract based on the appearance of Cr-EDTA in urine following an intra-ruminal dose. Increasing FI tended to reduce gastrointestinal tract permeability (P = 0.06). Limited interactions indicate that uNDF and FI act independently suggesting that increasing dietary uNDF, without increasing FI rate, can stimulate frequency of reticulo-ruminal contractions and reduce gastrointestinal permeability for finishing cattle.

PSIII-23 Maternal metabolizable protein level and rumen-protected methionine impacts on beef steer progeny gene expression in muscle and liver

This experiment evaluated how maternal metabolizable protein level and rumen-protected methionine supplementation during late gestation impacts expression of genes associated with fetal programming in beef steer offspring. In a 3 x 2 factorial arrangement, 138 Angus crossbred cows were randomly assigned one of three metabolizable protein (MP) treatments (fed to meet 90, 100, or 110% of MP requirements), with(without) 9 g/d of rumen-protected methionine (MET; Smartamine®M, Adisseo Inc.). The isocaloric diets were fed for the last 8 weeks of gestation. Steer progeny (n = 51) were assigned to one of seven pens by weight and received a common corn-based grower diet (58% corn silage, 26% alfalfa haylage, 15% soybean meal) for 47 days, followed by a finisher diet (78% high moisture corn, 12% alfalfa haylage, 8% soybean meal) for 115 ±31.5 days until slaughter. At slaughter, samples of Sternomandibularis muscle and liver were collected and snap-frozen in liquid nitrogen for RNA isolation and analysis of gene expression for growth, myogenic, and adipogenic genes. Data were analyzed using PROC GLIMMIX in SAS, with maternal MP level and MET supplementation as fixed effects, and pen as a random effect. Exceeding maternal MP requirements increased expression of myogenic regulatory factor, myogenin (MYOG; 90% MP: 0.72, 100% MP: 0.94, and 110% MP: 1.00; SEM = 0.083, respectively; P = 0.02) in muscle from steer progeny at slaughter. Methionine supplementation decreased expression of pyruvate kinase (PKM; MET: 0.81, No MET: 1.16; SEM = 0.092; P = 0.02) in muscle, which is associated with lean tissue growth. Maternal nutritional treatment did not influence hepatic gene expression (P ≥ 0.06). These data suggest that maternal nutrition may impact progeny muscle development, while maintaining metabolic function of the liver.

PSXIV-11 Silage source, physically effective neutral detergent fiber, and undigested neutral detergent fiber concentrations affect eating behavior, ruminal pH and reticular motility of finishing heifers

This study evaluated the effects of silage source, physically effective neutral detergent fiber (peNDF), and undigested neutral detergent fiber (uNDF) concentrations on eating behavior, ruminal pH, and reticular contractions for finishing beef heifers. Six Hereford′Simmental heifers (579±51.2 kg) were used in a replicated 6×6 Latin square (21-d periods) balanced for carry-over effects with 2×2 + 2 factorial treatment arrangement. Barley grain-based diets included barley (BarS) or wheat silage (WhS) at 10% of dietary DM. Silages were harvested at two chop lengths to yield low (LpeNDF) vs. high peNDF (HpeNDF) silage. For both BarS and WhS, chopped wheat straw was included (5% of DM) by replacing an equal proportion of LpeNDF silages to evaluate low vs. high uNDF (7.3 vs. 8.2% dietary DM) concentrations. Heifers fed HpeNDF WhS had greater DMI (silage′peNDF; P &lt; 0.01) than those fed HpeNDF BarS, but DMI did not differ for LpeNDF treatments. Ruminating and eating time increased for heifers fed HpeNDF WhS relative to LpeNDF WhS, but were not different for BarS (silage′peNDF; P ≤ 0.02). Increasing uNDF increased eating and ruminating times for heifers fed WhS, but not BarS (silage′uNDF; P ≤ 0.03). Mean ruminal pH averaged 5.97 and was not affected by silage, peNDF, uNDF, or the interactions (P ≥ 0.12). Feeding BarS increased the duration (384 vs. 256 min/d; P = 0.02) and area (84.5 vs. 43.8 pH×min/d; P = 0.02) that pH was &lt; 5.5 relative to WhS. Increasing peNDF numerically reduced the frequency of reticular contractions when fed BarS but numerically increased them when fed WhS (silage′peNDF; P &lt; 0.01). Reticular contractions were not affected by dietary uNDF concentration (P ≥ 0.13). These data highlight that at a constant inclusion rate, silage source and chop length interact to affect DMI, eating behavior, ruminal pH, and reticular motility indicating the need to account for silage type, peNDF, and uNDF in diet formulation for finishing cattle.

528 Late-Breaking: Late Gestation Metabolizable Energy Intake Increases Colostrum Yield and Alters Colostrum Composition in Beef Cattle

The objective was to determine how late gestation metabolizable energy (ME) intake impacts beef cow colostrogenesis. Angus-Simmental primiparous (n = 47) and multiparous (n = 109) cattle were blocked by expected calving date and randomly assigned to receive diets that supplied 80% (LME; n = 53), 100% (CME; n = 52), or 120% (HME; n = 51) of the ME requirement. Treatments were balanced by initial BW and fed for 53 d prior to calving. Cow body weight was recorded d -53, -39, -25, -10, and -3 relative to calving and retrospectively conceptus-corrected. Calves were weighed and measured prior to suckling. Colostrum was hand-stripped from all cows for compositional analysis and a subset (n = 16/treatment) was fully milked using a milking machine. Data were analyzed (PROC GLIMMIX) as a randomized block design, including the fixed effects of treatment, parity, and treatment×parity and the random effects of block and cow(block). Day and its interactions were included for repeated measurements. Treatment did not affect (P ≥ 0.73) cow BW or conceptus-corrected BW. Calf chest circumference was lesser (treatment×parity: P = 0.023) for primiparous vs. multiparous calves if their dams consumed LME or CME, but not if their dams consumed HME. Feeding HME rather than LME increased (P = 0.006) colostrum yield. The LME diet increased (P = 0.004) colostrum IgG concentration over HME; however, HME colostrum yielded more (P = 0.005) total IgG. Crude protein and urea-N were elevated (P &lt; 0.001) in LME colostrum, whereas HME colostrum contained more (P = 0.026) lactose. Low ME colostrum fat was greater (P = 0.013) than CME and beta-hydroxybutyrate was increased (P &lt; 0.001) in LME vs. CME and HME colostrum. These data provide insight regarding nutrient partitioning during late gestation and demonstrate that beef cow colostrogenesis is responsive to prepartum ME intake.

The effects of feeding benzoic acid and/or live active yeast (Saccharomyces cerevisiae) on beef cattle performance, feeding behavior, and carcass characteristics

Fifty-nine Angus-cross finishing steers were used to evaluate benzoic acid, active dry yeast (Saccharomyces cerevisiae), or a combination of benzoic acid and active dry yeast when supplemented in a high-grain finishing diet on live animal performance, feeding behavior, and carcass characteristics. Steers were fed a high-grain diet for the final 106 d of finishing. Treatments were as follows: no additional supplementation (CON), 0.5% benzoic acid (ACD), 3 g per head per day active dry S. cerevisiae (YST), or both 0.5% benzoic acid and 3 g/head per day S. cerevisiae (AY). Steers were weighed every 14 d, and ultrasound was performed for rib and rump fat thickness at the beginning (day 1), middle (day 57), and end (day 99) of the experiment. Insert feeding stations were used to collect individual feeding behavior data and DMI daily throughout. Blood samples were collected on days 21 and 22 and days 99-101 to assess plane of nutrition and metabolism. Ruminal fluid samples were collected by oral gavage 4 wk prior to slaughter. Carcass characteristics were examined at a federally inspected slaughter facility. Data were analyzed using PROC GLIMMIX of SAS with initial body weight (BW) as a covariate. Benzoic acid supplementation increased (P = 0.002) overall dry matter intake (DMI) compared to YST and CON steers, which may be due to a faster eating rate (P ≤ 0.008). Animal performance parameters (BW, average daily gain, feed conversion, and ultrasound fat depth) were not different (P ≥ 0.11) among treatment groups. Aspartate aminotransferase concentration was greatest (P ≤ 0.01) for YST steers, which may have been reflected in numerically greater liver abscesses. Carcass traits did not differ (P ≥ 0.33) among treatment groups. Ruminal pH was greater (P = 0.006) for ACD steers than AY steers (pH of 6.16 vs. 5.66, respectively), which indicated that there may be an interactive effect between benzoic acid and active dry yeast. To summarize, steers fed a high-grain finishing diet supplemented with benzoic acid, active dry yeast, or both benzoic acid and active dry yeast had similar growth performance and carcass characteristics compared to those without supplementation. However, the addition of benzoic acid alone increased DMI, variation in DMI, eating rate, and ruminal pH. Future studies are warranted to further investigate the impacts of benzoic acid on the ruminal environment of feedlot cattle.

The impacts of a fibrolytic enzyme additive on digestibility and performance in the grower and early finisher period, and supplemental Saccharomyces cerevisiae on performance and rumen health in the late finisher period for feedlot cattle

Two experiments were conducted to determine the effects of a fibrolytic enzyme pretreatment on growth performance, apparent total tract digestibility, and ruminal pH throughout the grower and early finisher period (exp. 1), and to examine the impact of Saccharomyces cerevisiae supplementation on intake, performance, and indicators of gut health in the late finisher period (exp. 2). A total of 54 steers were randomly assigned to a subgroup determining experimental treatment groups. In exp. 1, steers were randomized to control (CON1; no enzyme) or enzyme [ENZ; 0.75 mL·kg−1 dry matter (DM) of feed] dietary treatments. Digestibility was improved (P ≤ 0.05) in ENZ steers for DM, crude protein, net energy for gain, and sugars but did not affect (P ≥ 0.12) dry matter intake (DMI), average daily gain (ADG), or reticulo-ruminal pH. In exp. 2, the treatments were control (CON2; no yeast) or yeast (YST; 3.0 g·animal−1 daily) supplemented diets. Rumen papillae were collected for mRNA expression of gut barrier function (OCLN, CLDN, ZO1, and ZO2) and immune response (TLR2, TLR4, and FCAR) genes and histological measurements. Yeast supplementation decreased (P < 0.001) DMI by 31%, reduced variation in DMI, and improved feed conversion ratios but did not impact rumen health mRNA expression or histology measures (P ≥ 0.07). Overall, enzyme supplementation improved the digestibility of some nutrients in the grower period, and yeast supplementation improved feed efficiency, without impacting growth performance or gut health.

ASAS-NANP SYMPOSIUM: Applications of machine learning for livestock body weight prediction from digital images

Monitoring, recording, and predicting livestock body weight (BW) allows for timely intervention in diets and health, greater efficiency in genetic selection, and identification of optimal times to market animals because animals that have already reached the point of slaughter represent a burden for the feedlot. There are currently two main approaches (direct and indirect) to measure the BW in livestock. Direct approaches include partial-weight or full-weight industrial scales placed in designated locations on large farms that measure passively or dynamically the weight of livestock. While these devices are very accurate, their acquisition, intended purpose and operation size, repeated calibration and maintenance costs associated with their placement in high-temperature variability, and corrosive environments are significant and beyond the affordability and sustainability limits of small and medium size farms and even of commercial operators. As a more affordable alternative to direct weighing approaches, indirect approaches have been developed based on observed or inferred relationships between biometric and morphometric measurements of livestock and their BW. Initial indirect approaches involved manual measurements of animals using measuring tapes and tubes and the use of regression equations able to correlate such measurements with BW. While such approaches have good BW prediction accuracies, they are time consuming, require trained and skilled farm laborers, and can be stressful for both animals and handlers especially when repeated daily. With the concomitant advancement of contactless electro-optical sensors (e.g., 2D, 3D, infrared cameras), computer vision (CV) technologies, and artificial intelligence fields such as machine learning (ML) and deep learning (DL), 2D and 3D images have started to be used as biometric and morphometric proxies for BW estimations. This manuscript provides a review of CV-based and ML/DL-based BW prediction methods and discusses their strengths, weaknesses, and industry applicability potential.

Effect of silage source, physically effective neutral detergent fiber, and undigested neutral detergent fiber concentrations on performance and carcass characteristics of finishing steers

This study was designed to evaluate the effect of silage source (barley vs. wheat silage) when harvested at two chop lengths (low vs. high physically effective neutral detergent fiber [peNDF]) and when barley silage was partially replaced with straw to increase the undigested neutral detergent fiber (uNDF) concentration on performance and carcass characteristics of finishing steers. Four hundred and fifty yearling commercial crossbred steers with an initial body weight (BW) of 432 ± 30.5 kg were allocated to 30 pens and fed diets containing 90% concentrate:10% forage for 123 d in a completely randomized block design with a 2 × 2 + 1 factorial arrangement. Treatments included 1) barley silage (BarS) with low peNDF (LpeNDF); 2) BarS with high peNDF (HpeNDF); 3) BarS with straw to yield a diet with LpeNDF + uNDF; 4) wheat silage (WhS) LpeNDF; and 5) WhS HpeNDF. There were no silage × peNDF interactions for dry matter intake (DMI), average daily gain (ADG), or gain to feed ratio (G:F), but cattle fed WhS LpeNDF had a lower (P < 0.01) proportion of yield grade 3 and a greater proportion in yield grade 2 carcasses than cattle fed BarS LpeNDF or HpeNDF and WhS HpeNDF. Cattle fed WhS LpeNDF had greater (P = 0.02) incidence of severe liver abscesses when compared with cattle fed BarS LpeNDF or HpeNDF and WhS HpeNDF. Cattle fed BarS consumed less (P < 0.01) uNDF as a percentage of BW, had increased (P = 0.02) ADG, heavier (P = 0.02) hot carcass weight, with greater (P = 0.01) back fat thickness, and (P < 0.01) incidence of minor liver abscesses when compared with cattle fed WhS. Feeding HpeNDF did not affect DMI, ADG, or G:F, but increased (P = 0.02) marbling score and reduced (P < 0.01) the proportion AA quality grade and increased (P < 0.01) those classified as AAA when compared with cattle fed LpeNDF. Cattle fed low uNDF had lesser (P < 0.01) uNDF intake as a percentage of BW, greater dressing percentage (P = 0.01), had a lower (P < 0.01) proportion of carcasses in yield grade 2, and a greater (P < 0.01) proportion of carcasses in yield grade 3 when compared with cattle fed high uNDF. Thus, silage source, peNDF, and uNDF content do not impact DMI or G:F when diets contain 10% forage, but BarS relative to WhS as well strategies increasing the peNDF concentration may increase ADG, HCW, back fat thickness, dressing percentage, marbling score, and carcasses classified as quality grade AAA. Future research is needed to evaluate the usefulness of peNDF and uNDF in rations for finishing cattle.

83 The acute effects of feeding a grain-free diet with or without methionine, taurine or methyl donor/acceptor supplementation on plasma and whole blood amino acid concentrations in dogs

Grain-free pet foods have been sold for over a decade and comprise more than 40% of dog and cat diets sold today. Grain-free diets replace grain ingredients with pulse ingredients, which are high in lysine but low in methionine and cysteine, the precursor amino acids to taurine synthesis in the dog. The objective of this study was to evaluate the postprandial response of plasma methionine and taurine and whole blood taurine concentrations of dogs fed a grain-free diet without supplementation (CON) or with methionine (MET), taurine (TAU) or creatine, carnitine and choline (CCC) supplementation. Eight Beagles were pair housed and fed one of the four experimental diets for seven days in a 4x4 Latin Square Design. On the morning of d 7, cephalic catheters were placed and one fasted sample (0 min) and nine post-meal blood samples (15, 30, 60, 90, 120, 180, 240, 300 and 360 min) were collected. Data were analyzed as repeated measures using the PROC GLIMMIX function in SAS (Version 9.4). Dogs supplemented with MET had significantly higher plasma methionine concentrations from 30 to 360 minutes post-meal compared to dogs on CON, TAU and CCC treatments (P &lt; 0.05). However, no differences were observed in plasma methionine concentrations between CON, TAU and CCC treatments at any time point (P &gt; 0.05). Plasma taurine concentrations were significantly higher across time points in all treatment groups compared to CON (P &lt; 0.05). Whole blood taurine concentrations tended to be higher across time points in MET and TAU treatment groups compared to CCC (P = 0.0513). Overall, MET, TAU and CCC supplementation increased plasma taurine concentrations compared to CON, but only MET supplementation increased plasma methionine concentrations from 30 to 360 minutes post-meal.

PSIX-5 Fetal programming in an industry applied setting – Effects of feeding methionine during late gestation on progeny performance, feed efficiency, and carcass quality for feedlot steers

The objective of this study was to assess if rumen-protected methionine supplementation during gestation would impact male offspring performance and carcass quality in an applied setting. Sixty-seven gestating cows were randomly assigned to control (CON), or methionine (MET) treatments. Cows had ad libitum access to hay from a round bale feeder and were fed once daily in a bunk for approximately eight weeks prior to calving either: 0.75 kg/head/d of supplement pellet supplying 12 g rumen-protected MET/cow/d, or identical pellet with no added MET. The 34 steer progeny (MET n = 18; CON n = 16) were transported to a feedlot, assigned to one of seven pens by weight and fed a corn-based grower diet (58% corn silage, 26% alfalfa haylage, 15% soybean meal) for 47 days, followed by a finisher diet (78% high moisture corn, 12% alfalfa haylage, 8% soybean meal) for 115±31.5 days until slaughter. Body weights were recorded biweekly. Organ weights were recorded at slaughter. Carcass quality, meat quality, and rib composition were recorded 24 to 48 hours after slaughter. Data were analyzed using PROC GLIMMIX in SAS, with treatment as the fixed effect, and pen as the random effect. Supplementation of MET during pregnancy increased weaning weight (MET: 311, CON: 291 ±14.8 kg; P ≤ 0.001), final weight (ME: 668, CON: 631 ±16.8 kg; P = 0.01), and individual dry matter intake (MET: 13, CON: 12 ±0.5 kg/d; P = 0.04) during the finishing phase. There was no effect of maternal methionine supplementation (P ≥ 0.05) for average daily gain. Hot carcass weight was greater for MET steers (MET 372 vs. CON 353 ±9.5 kg; P = 0.03), while organ weights and carcass quality were not affected (P ≥ 0.05) by MET supplementation. This study showed that supplementing methionine during late gestation in an industry applied setting improved some offspring performance measures but did not result in enhanced carcass quality.

PSIX-4 Fetal programming – Maternal plane of nutrition effects on progeny performance, feed efficiency, and carcass quality for feedlot steers

To evaluate if maternal supplementation of protein and rumen-protected methionine during late gestation affects steer progeny performance and carcass quality, 138 Angus X cows were used in a 3 x 2 factorial arrangement of treatments. Cows were randomly assigned one of three protein treatments (feeding to meet 90%, 100%, or 110% of metabolizable protein (MP) requirements), with(without) 9 g/d of rumen-protected methionine (MET) and fed these isocaloric diets for ~8 weeks before parturition. Steer progeny (n = 56) were assigned to one of seven pens by weight and received a common corn-based grower diet (58% corn silage, 26% alfalfa haylage, 15% soybean meal) for 47 days, followed by a finisher diet (78% high moisture corn, 12% alfalfa haylage, 8% soybean meal) for 115±31.5 days until slaughter. Body weights were recorded biweekly. Monthly ultrasound images of back and rump fats were captured. Organ weights were recorded at the time of slaughter, with carcass and meat quality recorded 24 to 48 hours later. Data were analyzed using PROC GLIMMIX in SAS, with maternal treatment as the fixed effect, and pen as the random effect. Feeding to meet 90% MP requirements resulted in heavier calf weaning weights compared to 100% and 110% (262, 251, and 245 ±13.9 kg, respectively; P = 0.01). Maternal nutritional treatment did not affect average daily gain, dry matter intake, feed conversion during finishing or organ weights. Increasing dietary MP content from 90%, 100% to 110% reduced grade fat thickness (15.5, 14.7, and 11.8 ±1.11 mm, respectively; P = 0.04) and yield grades (2.7, 2.9, and 2.3 ±0.17, respectively; P = 0.04), but increased lean meat yield (49.5, 49.4, and 50.6 ±0.3%, respectively; P = 0.04). These data suggest that maternal MP content may alter steer progeny carcass traits while maintaining animal performance during the finishing period.

PSXII-11 The effects of feeding finishing cattle benzoic acid and/or live active yeast (Saccharomyces cerevisiae) on feeding behaviour, growth performance, and carcass characteristics

In a randomized complete block design, 59 Angus-cross finishing steers were used to evaluate the effects of benzoic acid, active dry Saccharomyces cerevisiae or a combination of both when supplemented in a high-grain finishing diet on feeding behavior, animal performance, and carcass characteristics. Steers were fed for 106 d (77% high-moisture corn, 16% alfalfa haylage, 6% soybean meal, 1% mineral and vitamin supplement with salt and limestone) containing: no supplementation (CON; n = 15), 0.5% benzoic acid (ACD; n = 14), 3 g/hd/d active dry S. cerevisiae (YST; n = 15), or both 0.5% benzoic acid and 3 g/hd/d S. cerevisiae (AY; n = 11). Every 14 d steers were weighed, and ultrasound images for rib and rump fat thickness were collected at the beginning, middle, and end of the experiment. Insentec feeding stations were used to collect individual animal feeding behaviour data and DMI throughout the study. Data were analyzed using PROC GLIMMIX of SAS with initial BW as a covariate. Benzoic acid supplementation increased (P = 0.002) overall DMI compared to YST and AY steers, which was due to faster eating rates for ACD steers (P ≤ 0.008). Individual animal DMI variation was greater (P = 0.001) for ACD and AY steers. Rumen pH was greater (P = 0.006) for ACD steers vs. CON and AY steers (6.16, 5.84, and 5.66, respectively). Growth performance measures were similar (P ≥ 0.11) between treatment groups. Aspartate aminotransferase concentrations in blood were greatest (P ≤ 0.01) for YST steers, which was reflected in greater proportions of abscessed livers at slaughter. Carcass characteristics did not differ (P ≥ 0.68) between treatment groups. The results from this experiment suggest that steers fed a high grain finishing diet supplemented with benzoic acid, Saccharomyces cerevisiae or both had similar growth performance and carcass characteristics as a control group. The addition of benzoic acid increased eating rate and elevated rumen pH, which was ultimately reflected in increased DMI.

Lessons from animal nutritionists: dietary amino acid requirement studies and considerations for healthy aging studies

Dietary restriction (DR) increases median life span and protects against age-related disease. Improved longevity can be achieved by restriction of dietary energy, protein, or amino acids (AAs), such as methionine (Met). Met requirements have been defined using methodologies that measure the dose response to Met when all other dietary variables are held constant and with outcomes focused on protein turnover. Here, we cover protein and sulfur AA requirements and discuss the terms "deficient," "optimal," and "excess" and how these need to be considered. We additionally discuss the effect of methyl-donating compounds on sulfur AA metabolism and outcomes. We will discuss how the mechanistic target of rapamycin complex 1 (mTORC1) signaling network regulates protein turnover, lipogenesis and cell growth, proliferation, differentiation, and metabolism in response to hormones, AAs, and cellular energy status. Inhibition of mTORC1 signaling with rapamycin or genetic mutation increases median life span in model organisms, and mTORC1 inhibition may be responsible for some of the life span-extending effects of DR. Finally, we discuss how the sulfur AAs may regulate aspects of reactive oxygen species (ROS) mitigation. Overall, we suggest that approaches evaluating AA intake need to consider whole-body protein synthesis and measures related to tissue-specific and whole-body metabolism that have been associated with longevity.

The influence of age and weaning on permeability of the gastrointestinal tract in Holstein bull calves

Fourteen Holstein bull calves were used in a randomized complete block design to investigate the effect of calf age and weaning on permeability of the gastrointestinal tract (GIT). Calves were randomly assigned to 1 of 2 treatments: (1) a weaning protocol that was initiated on d 35; WN; n=7), or (2) a control treatment where calves were not weaned (CON; n=7). Calves were bottle-fed milk replacer (150 g/L), in 3 equal portions/d targeting 15% of their body weight (BW) in liquid milk intake [approximately 21.1g/kg of BW/d, dry matter (DM) basis]. On d 35, the amount of milk replacer offered to WN calves was reduced to 7.5% of BW for 7 d before calves were weaned on d 42. On d 14, 28, and 42, calves were orally dosed with 500 mL of Cr-EDTA (179 mM Cr-EDTA solution) and housed in a metabolism crate to enable total urine collection and determination of total urinary Cr recovery as an indicator of total-tract permeability. On d 44, calves were killed and tissues from the rumen, omasum, duodenum, jejunum, ileum, cecum, and proximal and distal colon were collected, rinsed, and transported in buffer solution (pH 7.4 at 38.5°C). Tissues were incubated in Ussing chambers under short-circuit conditions with buffer solutions designed to mimic the mucosal and serosal energy source that would be available in vivo (glucose for tissues from the small intestine and short-chain fatty acids for tissues that would be exposed to fermentation; rumen, omasum, and large intestinal tissues). The serosal to mucosal flux of (14)C-mannitol and (3)H-inulin was measured for each region. Although we detected treatment × period interactions for BW and starter intake, dietary treatments did not differ within a week. Overall, the time that ruminal pH was <5.5 was less before weaning than after weaning. We observed a differential response for the appearance of Cr in urine for WN and CON calves, where the appearance of Cr (mg/48 h) in urine decreased for both treatments from d 14 to 28, but increased from d 28 to 42 for WN, whereas Cr appearance continued to decrease for CON. The flux of mannitol and inulin did not differ between treatments but did differ among region of the GIT, with rumen, duodenum, and jejunum having the greatest permeability. These data suggest that permeability of the GIT decreases with age but weaning may disrupt this process. The rumen, duodenum, and jejunum appear to be the regions with greatest permeability.

Effect of moderate dietary restriction on visceral organ weight, hepatic oxygen consumption, and metabolic proteins associated with energy balance in mature pregnant beef cows

Twenty-two nonlactating multiparous pregnant beef cows (639 ± 68 kg) were used to investigate the effect of dietary restriction on the abundance of selected proteins regulating cellular energy metabolism. Cows were fed at either 85% (n = 11; LOW) or 140% (n = 11; HIGH) of total NE requirements. The diet consisted of a haylage-based total mixed ration containing 20% wheat straw. Cows were slaughtered by block (predicted date of parturition), beginning 83 d after the initiation of dietary treatments and every week thereafter for 6 wk, such that each block was slaughtered at approximately 250 d of gestation. Tissue samples from liver, kidney, sternomandibularis muscle, ruminal papilli (ventral sac), pancreas, and small intestinal muscosa were collected at slaughter and snap frozen in liquid N2. Western blots were conducted to quantify abundance of proliferating cell nuclear antigen (PCNA), ATP synthase, ubiquitin, and Na/K+ ATPase for all tissues; PPARγ, PPARγ coactivator 1 α (PGC-1α), and 5´-adenosine monophosphate-activated protein kinase (AMPK) and the activated form phosphorylated-AMPK (pAMPK) for liver, muscle, and rumen; phosphoenolpyruvate carboxykinase (PEPCK) for liver and kidney; and uncoupling protein 2 (UCP2) for liver. Statistical analysis was conducted using Proc Mixed in SAS and included the fixed effects of dietary treatment, cow age, block, and the random effect of pen. Dietary treatments resulted in cows fed HIGH having greater (P ≤ 0.04) ADG and final BW than cows fed LOW. Abundance of ubiquitin in muscle was greater (P = 0.009) in cows fed LOW, and PCG-1 α in liver was greater (P = 0.03) in cows fed HIGH. Hepatic O2 consumption was greater in HIGH (P ≤ 0.04). Feed intake can influence the abundance of important metabolic proteins and suggest that protein degradation may increase in muscle from moderately nutrient restricted cows and that energy metabolism in liver increases in cows fed above NE requirements.

Posttransplant lymphoproliferative disorder presenting as multiple cystic lesions in a renal transplant recipient

We report a case of a 67-year-old man who experienced allograft dysfunction following a renal transplantation from a donation after cardiac death. The postoperative course was initially complicated by episodes of E. coli urinary sepsis causing pyrexia and a raised creatinine level. Ultrasound scanning 5 weeks posttransplant revealed mild hydronephrosis with several parenchymal cystic areas measuring up to 2 cm with appearances suggestive of fungal balls. Aspirated fluid again grew Escherichia coli, and this was treated with the appropriate antimicrobial therapy. The patient continued to have episodes of culture-negative sepsis; therefore, a computed tomography scan was performed 6 months posttransplant, which revealed multiple lesions in the renal cortex as well as liver and spleen. Subsequent biopsy revealed an Epstein-Barr virus-driven lymphoproliferation consistent with a polymorphic posttransplantation lymphoproliferative disorder (PTLD). This rare case of PTLD presenting as multiple renal, hepatic and splenic lesions emphasizes the need for a high index of clinical suspicion for this condition. Abnormal para-renal allograft masses should be biopsied to allow swift and effective management of a disease that can disseminate and become significantly more challenging to manage.

Inflammatory myofibroblastic tumours of the respiratory tract: paediatric case series with varying clinical presentations

OBJECTIVES

To highlight the clinical importance of inflammatory myofibroblastic tumours of the respiratory tract in children, and to present a case series of three children which illustrates this tumour's variable clinical presentation.

CASE HISTORY

The series includes: a nine-year-old girl with a diagnosis of juvenile idiopathic arthritis, who presented with finger clubbing and was found to have an inflammatory myofibroblastic tumour in her right upper lobe; a 15-year-old adolescent with a left main stem bronchial inflammatory myofibroblastic tumour, who presented with breathlessness and chest pain; and a 12-year-old girl with a tracheal inflammatory myofibroblastic tumour who presented with stridor. In each case, the tumour was resected surgically.

CONCLUSION

Inflammatory myofibroblastic tumour are a rare but clinically important and pathologically distinct lesion of the respiratory tract in children. The cases in this series highlight some of the varied clinical presentations of inflammatory myofibroblastic tumours, and illustrate some of this tumour's different anatomical locations within the paediatric respiratory tract.

Effect of crop residues in haylage-based rations on the performance of pregnant beef cows

Seventy-one individually fed multiparous, pregnant crossbred beef cows [body weight (BW) ± SD; 730 ± 77.9 kg] were used to examine the effects of including crop residues in alfalfa/grass haylage-based rations on BW gain, fat deposition/loss and plasma metabolites. The haylage control ration (CON; n = 23) was modified to include either 40% (dry matter basis) wheat straw (WS; n = 24) or 40% corn stalklage (CS; n = 24). Cows were blocked by calving date and randomly assigned to each treatment and fed for 82 d leading up to the earliest calving date. On days 1, 40, and 82, cows were weighed, ultrasounded to measure subcutaneous backfat (BF) over the ribs, body condition scored (BCS) and plasma was collected. Calves from cows fed WS had greater (P = 0.02 ) weaning weights than cows fed CS, but did not differ (P = 0.23) from CON. CS cows had the lowest ADG (P < 0.03), lost the most body condition (P < 0.04), and had the lowest dry matter intake (P ≤ 0.001). These data indicate that diets containing crop residues can be used to dilute high-quality haylage rations for wintering beef cows; however, diets containing 40% corn stalklage used in this experiment may not be advisable, since cows lost BW and fat, and their calves had the poorest calf performance up to weaning. Key words: Beef cattle, wheat straw, winter feeding, corn stalklage, crop residues

Effect of dietary corn silage inclusion on visceral organ mass, cellularity, and the protein expression of ATP synthase, Na+/K+-ATPase, proliferating cell nuclear antigen and ubiquitin in feedlot steers

Twenty-four steers (initial body weight = 535 ± 5.0 kg) predominately of Angus breeding were used to determine the effect of dietary corn silage inclusion [20, 40, 60, or 80% of dry matter (DM)] on visceral mass, cellularity, and the protein expression of ATP synthase, Na+/K+-ATPase, proliferating cell nuclear antigen (PCNA) and ubiquitin. Steers were fed at similar energy levels (2.1 × NEm requirement). There were no significant treatment effects on specific visceral organ weights. Hepatic Na+/K+-ATPase expression linearly increased (P = 0.01) and ruminal Na+/K+-ATPase expression linearly decreased (P = 0.01) with increasing corn silage inclusion. Hepatic PCNA expression was quadratically affected (P = 0.05) with a decrease when corn silage inclusion increased from 20 to 60%, and an increase when corn silage inclusion increased from 60 to 80%. Renal ATP synthase (P = 0.02) and ubiquitin expression (P = 0.01) were quadratically affected in a similar pattern with an increase when corn silage inclusion increased from 20 to 60%, and a decrease when corn silage inclusion increased from 60 to 80%. These results indicate that different dietary corn silage inclusions, at similar dietary energy intake, may alter rumen, liver, and kidney energy expenditure, at least in part, through changes in specific metabolism rather than mass. Key words: Corn silage inclusion, visceral organ mass, cellular energy metabolism, steer

Histological profile of tumours from MYCN transgenic mice

BACKGROUND

MYCN is the most commonly amplified gene in human neuroblastomas. This proto-oncogene has been overexpressed in a mouse model of the disease in order to explore the role of MYCN in this tumour.

AIMS

To report the histopathological features of neuroblastomas from MYCN transgenic mice.

METHODS

27 neuroblastomas from hemizygous transgenic mice and four tumours from homozygous mice were examined histologically; Ki67 and MYCN immunocytochemistry was performed in 24 tumours.

RESULTS

Tumours obtained from MYCN transgenic mice resembled human neuroblastomas, displaying many of the features associated with stroma-poor neuroblastoma, including heterogeneity of differentiation (but no overt ganglionic differentiation was seen), low levels of Schwannian stroma and a high mitosis karyorrhexis index. The tumours had a median Ki67 labelling index of 70%; all tumours expressed MYCN with a median labelling index of 68%. The most striking difference between the murine and human neuroblastomas was the presence of tingible body macrophages in the transgenic mouse tumours reflecting high levels of apoptosis. This has not previously been described in human or other murine neuroblastoma models.

CONCLUSIONS

These studies highlight the histological similarities between tumours from MYCN transgenic mice and human neuroblastomas, and reaffirm their role as a valuable model to study the biology of aggressive human neuroblastoma.

Acute renal failure due to mantle cell lymphoma – a case report and discussion of the literature

Acute renal failure secondary to lymphomatous infiltration of the kidneys is a rare manifestation raer mantle cell lymphoma (MCL). We present the case of a 76-year-old gentleman with acute renal failure an a background of previously treated low grade non-hodgkin lymphoma. At the time of presentation he complained only of mild lethargy und had no lymphadenopathy or organomegaly. Renal ultrasound revealed bilaterally enlarged kidneys and renal biopsy confirmed MCL. Mantle cell lymphoma runs an aggressive course and accurate diagnosis is very important in guiding appropriate treatment. This case demonstrates the importance of renal biopsy in the diagnosis of renal lymphomatous infiltration but also highlights the potential utility of histological examination in guiding targeted therapy.

Limitations in the ability of NB84 to detect metastatic neuroblastoma cells in bone marrow

BACKGROUND

The accurate assessment of metastases is an essential component of the staging process for children with neuroblastoma.

AIMS

To study the sensitivity of the immunohistochemical marker neuroblastoma 84 (NB84) for the detection of bone marrow infiltrates in children with stage 4 neuroblastoma.

METHODS

Primary tumour specimens, bone marrow trephine biopsy specimens and lymph node metastases, taken from children with neuroblastoma that had metastasised to bone marrow, were assessed with a panel of commonly used immunohistochemical markers for neuroblastoma. A comparison was drawn between the sensitivity of the marker NB84 for primary tumours and for bone marrow metastases.

RESULTS

NB84 immunolabelled all pre-chemotherapy and post-chemotherapy (n = 24) paired primary tumour specimens, as well as each of a further 20, unpaired, pre-chemotherapy primary tumour specimens. It also labelled all (n = 4) lymph node metastases. Immunolabelling of bone marrow trephine biopsy specimens (21/33) was less sensitive. Of 16 primary tumour specimens with a paired bone marrow trephine biopsy specimen, all immunostained positive, whereas only 62.5% of bone marrow biopsy specimens immunostained positive for NB84. The number of bone marrow biopsy specimens immunostaining for NB84 was significantly lower than the number of paired primary tumour specimens (p = 0.041).

CONCLUSIONS

NB84 remains a useful marker for the diagnosis of neuroblastoma in primary tumour specimens, but not for neuroblastoma that has metastasised to bone marrow.

Follicular dendritic cell tumour in a 9-year-old child

Follicular dendritic cell tumour (FDCT) or sarcoma is a rare tumour first described in 1986. Some 80 cases have been reported, the youngest being in teenagers. Our patient first presented at 9 years of age with a cervical mass that was removed and revealed an apparently benign, but florid reactive process. At age 14 the lump recurred and biopsy was diagnostic of FDCT. Radical block dissection showed disease to level III and 6 weeks of radiotherapy was followed by 6 months adjuvant chemotherapy. Three years after completing his final treatment he shows no signs of recurrent disease.

T-cell lymphoma presenting as acute mastoiditis with a facial palsy

Isolated T-cell lymphomas affecting only the mastoid are extremely rare. Presentation with oto-neurological signs prior to systemic involvement of a lymphoproliferative disease is also unusual. This is the youngest reported patient with a peripheral T-cell lymphoma with disease isolated only in the mastoid who presented with acute mastoiditis and a complete seventh cranial nerve palsy.

Tyrosine phosphorylation in human lymphomas

In a previous study, we showed that the high level of protein tyrosine phosphorylation present in lymphomas containing an anaplastic lymphoma kinase (ALK) can be demonstrated in routinely processed paraffin tissue sections using immunolabelling techniques. In the present study we investigated whether oncogenic tyrosine kinase activation also occurs in other categories of lymphoma by staining 145 cases of lymphoma covering those tumours with a range of different subtypes including those with morphological similarity to ALK-positive anaplastic large cell lymphoma (ALCL). Twelve cases of the borderline malignant disorder lymphomatoid papulosis were also studied. Twenty seven of the 28 cases of ALK-positive ALCL showed the extensive cytoplasmic labelling for phosphotyrosine in the neoplastic cells. The remaining case containing moesin-ALK exhibited membrane-associated phosphotyrosine expression. There was no nuclear phosphotyrosine labelling in any of the ALK-positive ALCL, even though ALK was present within the cell nuclei in 23 of the tumours. Variable degrees of phosphotyrosine labelling, usually membrane-restricted, were observed in 7/40 cases of ALK-negative ALCL, 9/29 cases of diffuse large B-cell lymphoma, 3/6 cases of mediastinal B-cell lymphoma, 2/7 cases of Hodgkin's lymphoma, 3/6 cases of peripheral T-cell lymphomas unspecified, 4/6 cases of B-cell chronic lymphocytic leukaemia, 2/6 cases of follicular lymphomas and 2/12 cases of lymphomatoid papulosis studied. However none of these phosphotyrosine-positive cases showed the strong cytoplasmic labelling comparable to that seen in ALK-positive lymphoma. We conclude that activation of a tyrosine kinase is probably not a major oncogenic event in lymphomas other than ALK-positive ALCL.

Loss of nuclear expression of the p33(ING1b) inhibitor of growth protein in childhood acute lymphoblastic leukaemia

BACKGROUND/AIMS

p33(ING1b) is a tumour suppressor protein involved in growth control and apoptosis. Suppression of p33(ING1b) expression is associated with the loss of cellular growth control and immortalisation, whereas its overexpression causes cell cycle arrest. Moreover, normal p33(ING1b) expression is essential for optimal function of p53. Acute lymphoblastic leukaemia (ALL) is the most common malignancy of childhood, accounting for one third of all childhood malignancies. A variety of cytogenetic abnormalities have been described but there is no single abnormality common to all cases. Deregulation of the TP53 pathway is a common genetic abnormality in human malignancies. However, TP53 mutations are uncommon in ALL. It is possible that alternative mechanisms of regulation of the TP53 apoptosis pathway, such as modulation of p33(ING1b) expression, may be important in ALL. The aim of this study was to assess the expression of p33(ING1b) in childhood ALL.

METHODS

One hundred and forty five patients with childhood ALL were investigated in this immunohistochemical study of the expression of p33(ING1b).

RESULTS

Loss of nuclear expression of p33(ING1b) was seen in 78% of cases. This was associated with increased cytoplasmic expression of the protein. Kaplan Meier survival analysis demonstrated a trend towards a better prognosis for patients with tumours that had lost nuclear p33(ING1b).

CONCLUSION

These results suggest that the loss of nuclear p33(ING1b) expression may be an important molecular event in the pathogenesis of childhood ALL.

Monoclonal antibodies recognizing CD5, CD10 and CD23 in formalin-fixed, paraffin-embedded tissue: production and assessment of their value in the diagnosis of small B-cell lymphoma

AIMS

Assessment of the expression of antigens CD5, CD10 and CD23 can be of value in the differential diagnosis of small B-cell lymphoma. Correct subclassification is important since optimal treatment regimes differ between the subtypes. The aim of this study was to generate monoclonal antibodies recognizing these antigens in paraffin-embedded tissue and to assess their efficacy using a panel of cases of small B-cell lymphoma of various subtypes.

METHODS AND RESULTS

For each antibody synthetic recombinant protein and conventional murine hybridoma technology was employed. Monoclonal antibodies effective in formalin-fixed, paraffin-embedded tissue were successfully generated, designated NCL-CD5-4C7, NCL-CD10-270 and NCL-CD23-1B12, respectively. A series of 58 cases of small B-cell lymphoma including examples of each subtype (lymphocytic, follicle centre cell, mantle cell, marginal zone and lymphoplasmacytoid) was assembled and immunostaining for the respective antigens carried out using the monoclonal antibodies produced. Our results indicate that the antibodies are specific for their respective antigens and give the predicted phenotypic profile in the small B-cell lymphoma subtypes.

CONCLUSIONS

These novel monoclonal antibodies may be of value in routine diagnostic practice.

Defective IkappaBalpha in Hodgkin cell lines with constitutively active NF-kappaB

The molecular mechanisms underlying Hodgkin's disease remain obscure, but it has been recognized that the neoplastic cells display high levels of constitutively active nuclear NF-kappaB. Here we demonstrate that although nuclear NF-kappaB is transcriptionally active, the Hodgkin cells fail to activate NF-kappaB dependent transcription in response to CD40 ligand. In three Hodgkin cell lines examined each had abnormalities in expression of IkappaBalpha which could account for the deregulated NF-kappaB. Although all three cell lines had greater than normal levels of IkappaBalpha mRNA no IkappaBalpha protein could be detected in the KM-H2 cells, while the L428 cell line contains a C-terminally truncated IkappaBalpha species that fails to associate with NF-kappaB. The HDLM-2 cell line contains a more slowly migrating form of IkappaBalpha that can associate with NF-kappaB, but increasing the level of this protein within the cell fails to inhibit nuclear NF-kappaB. Addition of recombinant IkappaBalpha to nuclear extracts from all three cell lines resulted in complete inhibition of NF-kappaB DNA binding activity and introduction of a plasmid expressing IkappaBalpha into the cells inhibited the transcriptional activity of an NF-kappaB dependent reporter plasmid. Thus the constitutive expression of NF-kappaB in Hodgkin cells is a direct consequence of the abnormal expression of IkappaBalpha rather than changes in NF-kappaB that render it refractory to inhibition by IkappaB proteins. These changes could, at least in part, account for the characteristic activated phenotype of Hodgkin cells and their pattern of cytokine secretion, which determine the pathological appearance and clinical manifestations of Hodgkin's disease.

Reviewing practice expenses can improve profitability

Many physician group practices--particularly practices that have been acquired by hospitals and integrated delivery systems--are experiencing expense increases and productivity decreases. Physician group practices can take steps to reverse these unfavorable trends by carefully reviewing and benchmarking practice costs related to physician compensation plans, support staff salaries and benefits, occupancy costs, clinical supply costs, and malpractice insurance. Group practices also can improve cost management and resource utilization by creating an operating budget based on historical expenditures and anticipated revenues and by comparing it with peer benchmarks.

Overcoming the physician group-hospital cultural gap

In order for integration between physician practices and hospitals to be successful, each will have to overcome cultural differences that have contributed to a sometimes adversarial relationship. Such differences can be attributed to opposing views related to focus, perspective, working environment, decision making, goals, working style, and management style.

Detection of anaplastic lymphoma kinase (ALK) and nucleolar protein nucleophosmin (NPM)-ALK proteins in normal and neoplastic cells with the monoclonal antibody ALK1

The t(2;5)(p23;q35) translocation, associated with anaplastic large-cell lymphoma (ALCL), results in the production of the nucleolar protein nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) protein. This report describes an immunocytochemical study of the distribution of ALK and NPM-ALK proteins using a new monoclonal antibody, ALK1, that recognizes a formalin resistant epitope in both the 80-kD NPM-ALK chimeric and the 200-kD normal human ALK proteins. Cytoplasmic and nuclear labeling was seen in the t(2;5)+ SU-DHL-1 and Karpas 299 cell lines. Normal ALK protein expression was restricted to the central nervous system (in scattered neurons, glial cells, and endothelial cells). Two hundred and thirty-nine cases of lymphoma and 80 nonhematopoietic tumors were immunostained. Antibody ALK1 labeled 53.4% (39 of 73 cases) of CD30+ ALCL. A case of ALCL with a t(1;2) translocation was ALK1+. Three cases of CD30- ALCL with prominent nucleoli showed a unique pattern of coarse granular cytoplasmic labeling. All other tumors, including Hodgkin's disease and lymphomatoid papulosis, were ALK1-. These results indicate that reliable immunostaining of routine biopsy material for NPM-ALK and ALK proteins is feasible. Such analysis is of diagnostic importance, especially because t(2;5)+ ALCL cases have a good prognosis with appropriate treatment.